RR/UK: add connect viewset to return authenitcated user profile
LW: store _user attribute with the username of the requesting user
LW: set the _user meta on rest service output
LW: renamed _user to _submitted_by
LW: flake8
LW: fixed tests to expect _submitted_by
LW: only use _submitted_by in rest service output
UK: delete temp file after export
UK: remove attachment.full_filepath, prevent creation of unnecessary temp files
UK: pep8
UK: compare sorted values
UK: use try .. finally to close temp_file
UK: code refactor: ensure file is closed properly
PLD: remove unused streaminghttpresponse
PLD: use helper to build HttpResponse
PLD: close zips if finally if not none
Merge pull request #387 from onaio/fix-memory-issues

delete tmp files after use for attachment export
PLD: more project tests
PLD: remove unneeded iteration
Merge pull request #391 from onaio/project-tests

Project tests, green here, https://travis-ci.org/onaio/onadata/builds/29378462